Examining the Viability of Windows Impact/Update Method for Delay Analysis in Construction Disputes

Samer Skaik School of Built Environment, Heriot Watt University, Dubai Campus, United Kingdom.

email: S.Samer@hw.ac.uk Krishnakumar P NAIR

School of Built Environment, Heriot Watt University, Dubai Campus; United Kingdom. email: kkumar105@hotmail.com

Abstract

Nowadays, construction delay disputes often end up on the arbitration route where the delay experts appointed by the parties advise the tribunal on the extension of times entitlements of the parties. For this purpose, the identification and quantification of concurrent and pacing delays are integral aspects of resolving these disputes using a proper delay analysis methodology. The aim of the study is therefore, threefold. Firstly, the available literature on the concurrent and pacing delays are analysed in detail to establish the principles for the evaluation of the concurrency and pacing delays. Secondly, a robust delay analysis methodology called ‘windows impact/update method’ is explained often used by the experts for the effective quantification of concurrent and pacing delays. This methodology is an improved version of time impact analysis and normal windows analysis. For better demonstration, the explanation of the methodology is facilitated with the help of a typical case study analysis. Finally, the principles of concurrency and pacing, as explained in the literature review, are promptly applied to the case study results to show the applicability of the analysis method on any types of delay disputes. The study shows the effectiveness of the windows impact/update method for the quantification of the concurent and pacing delays.

Keywords: Concurrency, Pacing, Windows Impact/Update Method, Arbitration, Expert Witness

1. Introduction Historically, the evaluation of the extension of time and quantifying the various aspects of delays such as EOT, concurrent delays, pacing delays and and compensation for delay in construction is a disputed field of work (Gibson 2008). Once the dispute is excalated to the arbitration route, then the delay analysis would be carried out by ‘expert witnesses’. The experts are appointed to give evidence on the aspects of either ‘delay’ or ‘quantum’ matters and their opinion may be in the form of a report called expert witness report and they will be cross examined in the court of Arbitration (Uff 2005).

To facilitate an independent report, the experts use the most appropriate delay analysis methodology. Even though there are many delay analysis methodologies available, a common-sense approach using an analysis method which uses contemporaneous progress is preferred. That is the reason the experts normally use windows impact/update method which is an ‘actual’ based method which can effectively quantify the concurrent and pacing delays.

The sections below review the principles of concurrency and pacing together with the procedure of conducting windows impact/update method. Further to this, these principles are tested with a sample case study which will illustrate the quantification of all aspects of delays.

2. Research Methodology

Even though there are many methods for conducting research, the case study analysis is one of the best qualitative research methods. Denzin and Lincoln (1994) defined qualitative research as the“...studied use and collection of a variety of empirical methods – case study, personal experience, introspective, life story, interview, observational, historical, interactional, and visual texts…”. Further Creswell (2007) explained that the case study research is the study of an issue or issues explained through one or more case studies. Therefore, the authors will use case study analysis as the research analysis method for this particular study.

Through research, the authors will collect all the information related to the case study from the lead expert witness related to a construction delay dispute and then discuss and interpret the results from the case study as explained in the relevant sections.

3. Concurrent Delays

Quite often in contraction contracts, the delays do not necessarily act alone but occur as a combination. When more than one delay event occur at the same time, then these delay events are said to be concurrent delays. In a first glance, there seems to be no agreement in analysing and calculating the concurrent delays due to differing legal principles. This is because of the fact that it requires the consideration of many factors affecting the contract such as the level of criticality of activities & technical integrity of the programme, float, the time of occurrence of the delays and their criticality, identification of the pacing delays, method of delay analysis, contractual provisions in the contract as well as legal provisions applicable to the contract. However, over the course of time, some approaches were developed for the identification and quantification of concurrent delays as discussed below.

3.1 Identification of concurrency

In order to verify that the delays in question are valid concurrent delays, first check would be to decide whether the delays are concurrent or consecutive as suggested by Gibson (2008). This can be done by reviewing the project critical path; delays will generally be consecutive unless there are two or more than two critical paths. For two delays to be concurrent, both of them should impact the critical path. Even if there are multiple critical paths in a project, it is quite un-common for the true concurrency to occur. Once it is established that there are concurrent delays present, then the delays have to be analysed further to identify and calculate two separate issues which are (A) calculate EOT entitlement in a concurrent delay situation and (B) calculate the total compensable period for which the employer should pay compensation and the period for which the employer can levy LDs.

3.2 Concurrent Delay Principles This section reviews in brief the current literature available on the topic of quantification of concurrent delays.

3.2.1 The Devlin approach As indicated by Williamson (2005), the Devlin approach is based on the judgement by Judge Devlin in a UK case1 as explained in ‘Keating on building contracts (para 8-25)’. Based on this approach, if there are two concurrent delay events one of which is an excusable compensable delay event and other is a contractor culpable delay event or even a neutral event, then the contractor would be able to recover time and cost. However, Pickavance (1997) indicated that the learned authors of Keating considers that this approach is not strictly applicable for contraction contracts because it would result in a scenario where both the Employer’s claim for LDs and the Contractor’s claim for loss and expense could succeed.

3.2.2 The Burden of Proof approach

Pickavance (1997) explained that if there are two causes and the claimant in in breach of contract, it is down to the claimant to show that the loss was caused otherwise than by his breach. Again, Pickavance (1997) indicated that the learned authors of Keating considers this method is very difficult to use in concurrent delay situations as both the claimant’s claims for loss and expense and respondent’s claim for LDs will fail as it has the opposite effect of Devlin position.

3.2.3 The Dominant Cause approach

This approach suggests that if there are two cause of delay, the effective or the dominant cause is to be considered as the deciding factor for the delay. Unlike the previous two approaches, this approach can be applied to alleged concurrent delays by seeking to establish which is the dominant cause of any particular period of delay; with the successful party being entitled to his loss and expense or liquidated damages as applicable. However, Pickavance (1997) stated that the dominant cause approach is a legal theory relevant to recovery of damages; not to provide relief from damages. There are many UK court cases2 where the court rejected the dominant cause approach to calculate EOTs in concurrent delay situations. Further, Thomas & Wright (2011) pointed out based on ‘Keating (para 8.021)’ opinion that                                                                                                                          1  Heskell v Continental Limited [1950] 1 All England 1033  

2  H. Fairweather and Co Ltd v London Borough of Wandsworth (1987) 39 B.L.R. 112

the dominant cause approch should not be used in extension of time situations, but can be applied to calculate compensation (or compensation periods) after the EOT has been identified and quantified.

3.2.4 The Malmaison approach

The famous Malmaison case3 in UK in 1999 provided recommendations on the concurrent delay scenarios. The Judge Dyson in his judgement accepted that: “……if there are two concurrent causes of delay, one of which is a relevant event, and the other is not, then the contractor is entitled to an extension of time for the period of delay caused by the relevant event notwithstanding the concurrent effect of the other event. Obviously, the Society of Protocol (2002) supported this approach for the calculation of EOT. Core Principle 9, which deals with concurrent delay for computing EOT states that where concurrent delay occurs, the Contractor’s concurrent delay should not reduce any EOT due to the Contractor. This approach was further supported in many UK cases4. Kheng (2003) suggests that the favourable method is the Malmaison approach on EOT even though there is a clash between the Malmaison approach and the dominant cause approach on concurrency. However, as explained by Thomas and Wright (2011) based on the views of ‘Keating on Building Contracts’ this approach is best suited to calculate EOT in concurrency.

3.2.5 Apportionment

Williamson (2005) commented about this approach based on the view of ‘Keating on Building Contracts’ that where there are two competing causes of delay of equal or relative causative potency, this approach suggests that the time overrun and its consequences should be ‘apportioned’ between the contractor and the employer on the basis to their relative causative potency. This approach is applicable in cases where the causes of the loss are truly concurrent in the sense that both causes operate together at the same time to provide a single consequence. Thomas and Wright (2011) also agreed to this apportioning of liability in case of concurrent delay events.

In a recent Scottish case5, Lord Drummond Young made his judgement based on the dominant cause approach and apportionment approach for the quantification of concurrent delays related to EOT and compensation. However, as stated by Eyssell (2010), UK courts have not yet supported the apportionment approach for compensation in concurrent delay situations and they are still following ‘all or nothing’ on approach to liability. However, the authors consider that this is a good approach if it can be applied in a balanced way as it can satisfy the rule of ‘natural justice’ which is the basis of common law (Uff 2005).

3.2.6 First –past-the-post approach

As pointed out by Gibson (2008), this is based on the logic that the cause of delay, which occurs first in terms of time, will be used first to evaluate the impact on delay to completion. All the other causes of delay will be ignored unless they affect the completion date and continue after the first cause has

                                                                                                                         3 Henry Boot Construction (UK) Ltd. V Malmaison Hotel (Manchester) Ltd (1999) 70 ConLR 32

4  Royal Brampton Hospital NHS Trust v Hammond & Ors(No 7) [2001] 76 Con LR 148

5  City Inn Limited v Shepherd Construction [2007] CSOH 190  

ceased to have any delaying effect. In this case, only the latter part of the second delay will be relevant to the calculation of an extension of time.

3.3 Recent guidelines in concurrency by practitioners

Gibson (2008) agrees with the SCL Protocol (2002) on the issue of calculation of EOT in concurrency situation and concludes that the most popular guideline for calculating EOT in concurrency is the use of malmaison approach. Therefore the authors consider that the Malmaison approach is best method suited for the calculation of EOT in concurrency situations.

For the calculation of compensation and compensation periods, Thomas & Wright (2011) tried to establish the principles with the help of conclusions made in ‘Keating on Building Contracts, eighth edition (pages 271-6)’ and other authors. These are:

1. Reimbursement of loss and expense is allowed if the compensable excusable delay is on the critical path and the non-compensable delay is non-critical;

2. No reimbursement of loss and expense is allowed if a compensable excusable delay is non-critical or not on critical path and a non-compensable delay is on the critical path;

3. No reimbursement of loss and expense should normally allowed if both the non-compensable delay and the compensable excusable delay are on parallel critical paths and are of the same duration;

4. If a compensable excusable delay event occurs first followed by a non-compensable delay event (with both delay events being on the same or parallel critical paths), recovery of loss and expense is normally permitted;

5. When a non-compensable delay event occurs first followed by a compensable excusable delay event (with both delay events being on the same or parallel critical paths), there are grounds to argue that no reimbursement should be permitted.

As indicated by Thomas & Wright (2011) and the authors too agree that the departure from the above guidelines occur time to time but in rare situations only. Therefore, the authors recommend the malmaison and dominant cause approaches to calculate the EOT and compensable periods (or compensation) in a concurrency situation respectively. Also, the apportionment for the calculation of concurrency is widely used in USA, but the UK has not yet started to apply this. Nevertheless, the authors consider that this could be a good method if applied in a controlled and balanced way.

4. Pacing Delays

In the construction industry pacing is best explained as ‘work expands to fill available time’ which is similar to the saying ‘gas expands to fill available space’ (Rider & Long 2013). It is not un-common for an employer caused critical path delay to extend the performance of other non-affected contractor’s activities, which consumes the available float due to the employer delay. This is called as pacing.

As indicated in the SCL Protocol (2002) and as pointed out by Gibson (2008), the employers are not liable to pay costs to the contractor if a contractor culpable delay is occurring simultaneously with the employer culpable delay. However, it is seen in most of the cases that when the employer culpable excusable delay occurs, the contractor slows their work considerably. As commented by Keane & Caletka (2008), the contractor’s rationale in this situation will be “why should I hurry up and then

wait?” The name “pacing’ rightly emerged from this scenario. For this pacing delay to be considered by the other parties or by the arbitration tribunal, the contractor should make sure to prove that the contractor culpable delay is not an independent delay, but an after effect of the employer’s culpable delay (Bramble & Callahan 2011).

AACEI’s Recommended Practice 29R-03 (2011)6 explains that the aspect which separates the pacing delays from the concurrent delays is that pacing is an effect of a conscious choice by the party (either contractor or the employer) to carry out the works at a slow rate. This might be due to their prior knowledge that contemporaneous delay in an activity by the other party is already delaying the completion and therefore, they do not want to complete the works first and then wait for the delayed works to complete. On the other hand, concurrent delays are independent of each other with no conscious effort from both the parties to slow down the works.

4.1 Pacing & compensation

As evident from the above, in a pacing delay situation, the contractor is only consuming the additional float created by an already occurred employer delay. Rider & Long (2013) explains that the right to pacing is acceptable due to the fact that the available float is shared between the parties. The SCL Protocol’s (2002) view is also consistent with this as the protocol indicates that the float is recommended to be consumed by the party who requires it first and can be shared between the parties too. However, if the contractor is responsible for the delays due to lack of resources, then this cannot be considered as pacing, as it will be just contractor culpable delays.

Once agreed in the dispute situation, pacing delay changes the compensability of the delays in a concurrent delay situation (Rider & Long 2013). If the contractor’s pacing is acting with the employer delay, then the delay is excusable and compensable to the contractor. Similarly, if the employer is pacing with the contractor’s culpable delay, then the delay is compensable to the employer but non-excusable and non-compensable to the contractor. Therefore, the identification of pacing is very important in the context of the construction delay disputes.

4.2 Identification of pacing delay

In order to identify pacing delay situation in a typical construction delay dispute, AACEI RP 29R-03 (2011) and Keane & Caletka (2008) provided some guidelines as indicated below. If the contractor is putting forward the pacing argument, they should provide evidence for the below items.

1. A predecessor dependent delay should precede a pacing delay, which is a minimum requirement to have a pacing delay to exist;

2. Evidence that the contractor could resume progress on a paced activity with the original output (or un-paced rate);

3. Evidence of an express decision to pace the works; and finally 4. The contractor should produce evidence that the pacing was a conscious and deliberate decision

from their part at the time of pacing. This should be in the form of a letter to the employer with their intention to pace the works.

                                                                                                                         6  Recommended Practice 29R-03 – Forensic Schedule Analysis published by AACEI in 2011  

Without these four conditions met, a pacing delay will not be identified and recognised in a dispute. Keane & Caletka (2008) considers that when pacing delays are argued with hindsight, it should be treated with both caution and scepticism especially when the assertion is unsupported by contemporaneous records. Based on this, if no documentation is made available to justify pacing delay, then the contractor’s concurrent delays shall not be considered as pacing delays and the contractor should face the consequences of the resulting concurrent contractor culpable delays.

5. Windows Impact/Update Delay Analysis Method

Farrow (2001) indicated that experts always prefer a common-sense based delay analysis method which uses contemporaneous progress data over other theoretical methods. Out of all the methodologies available which are used in the industry, the widely accepted methodology is considered to be Tim Impact Analysis or simply called as TIA (SCL Protocol 2002). This is due to the fact that TIA takes account of the progress of the works at the time of the delay, mitigation of the delays, concurrent delays etc. However, Pickavance (1997) considered that ‘window analysis’, which is similar to TIA, is equally effective as the TIA. Pickavance (1997) noted that the window analysis, which focuses on sequential periods of project performance (windows) on a contemporaneous critical path, has significant benefits over other methods. He commented that since this method is based on the actual progress (not theoretical), it is considered to be a robust method of analysis.

Farrow (2001) indicated that an updated version of the windows and TIA called ‘the windows impact/update method’ is the best method to calculate the various aspects of delays. Using this impact/update method under window analysis, the delay events are impacted into the contemporaneous progress updated programmes on a month by month basis (the windows) to calculate the monthly entitlement as well as the contractor’s actual performance (whether slow progress or acceleration) for that month or model. Kelly (2013) also agrees to the acceptance of windows method as the most effective method for conducting forensic schedule analysis. The windows impact/update method makes the process of calculating EOT periods and compensable periods easy even if concurrent delays are present. That is why Farrow (2001) considers that this is one of the best methods.

The pre-requisites to conduct a windows impact impact/update analysis are:

1. A logic linked proper CPM networked programme preferably in primavera software (called as the ‘baseline programme’);

2. Periodically (weekly/monthly) updated contemporaneous as-built programmes based on the baseline;

3. A strategy to divide the total contract duration in to a number of windows based on project milestone dates, start/end of a major delay events or based on progress update periods (monthly or every two months etc.);

4. Chronologically listed delay events affecting the project; and 5. Properly networked delay fragnets which represent the delay events; Once the above stated details of the project are ready, then the expert can start the delay analysis. As the name suggests, the sequence of this window analysis is to impact first followed by updating as explained below. For carrying out the ‘impact’ part of the window analysis on window 1, the first step

is to insert the delay fragnets (the activities representing the delay events) present in this window 1 period into this programme to time impact their effect. This process is indicated in figure 1 below.

Figure 1 :Example: Impact of delay events for W1

When this programme is rescheduled, if the completion date has moved forward, the difference between the revised completion date and the baseline complete date is the EOT entitlement to the contractor due to the delay events. This process is shown in the figure 2 below.

For the ‘updating’ part of the analysis, a copy of this window 1 impacted programme is made and then this programme is updated with actual progress achieved during the first window period. Then reschedule the programme to determine the effect of progress inserted. If the completion date has moved to a later date, then the contractor is culpable for the additional period of delay as shown in figure 3 below. However, if the completion date has moved to an earlier date, then the contractor has managed to mitigate part of the delay.

Figure 2 : Impact delay from W1 Figure 3 : Update delay from W1

This iterative process is then repeated for window 2 and so on until the last window. As the analysis commences with the baseline programme and ends with a re-scheduled programme at the end of the last window, any effect upon completion date is allocated incrementally to the contractor or to the employer. The total EOT is calculated by considering the sum of the delay results that are calculated in each window (after the ‘impact’ process) which represents the overall time extension for the project. In each window, a comparison of the ‘impacted’ programme completion date to the ‘updated’ (as-built) programme actual completion date determines:

1. The amount of contractor culpable delay in the as-built programme that is subject to delay damages (penalties) if the as-built completion date is later than the impacted completion date.

This means that the concurrent delay due to the contractor culpable delays (slow progress) is the critical delay and therefore, the contractor is only entitled for EOT but no compensation.

2. The amount of acceleration that the contractor has accomplished if the as-built completion date is earlier than the update impacted completion date.

The strength of this approach is that it takes into consideration actual progress and revised programme intent in a logical manner. Issues such as mitigation, criticality, concurrency, and dominance are all taken into account in a transparent manner, leading to a better understanding of what occurred and the circumstances at the time the events occurred. Therefore, the expert reports prepared with this window impact/update analysis provides the tribunal or court enough evidence on the merits on the case with which they can make their judgements.

Once the above analysis of windows is completed, next step is to calculate the various matters related to the delay such as the contractor culpable delays, concurrency, pacing and compensable periods etc. This is explained with the help of a case study analysis in the following section.

6. Case Study Analysis 6.1 The Case study Project & Dispute

In order to test the concurrency and pacing principles as concluded in the study above, a case study project (construction of Tower + Car park) was analysed using windows impact/update method. The total project duration of 1,268 days (original time for completion of 700 days + 568 days of delays) was broken down in to 11 windows as indicated below based on the start/finish of major events.

Figure 4 : Case study project delay analysis - Splitting of windows

The windows impact/update delay analysis essentially consisted of the following operations:  

1. Copy the baseline programme and rename it as programme K01A to start window 1 analysis; 2. To start the ‘impact’ process, insert the fragnets of delay events present in this window 1 period

into this window 1 programme for analysis of their effects. 3. Reschedule the programme to calculate any entitlement to an extension of time. If the

completion date has moved forward, the difference between the new date and the original complete date is the entitlement to the claimant due to the delay events for window 1. If there is no change to date then there are no contractor culpable delays.

4. To start the ‘update’ process of the analysis, copy this impacted programme for window 1 and rename it as programme K01B for updating progress;

5. Update the programme with actual progress achieved during the first window period; 6. Then reschedule the programme to determine the effect of progress being inserted. If the

completion date has moved to a later date, then the claimant is culpable for the additional period of delay. If the completion date has moved to an earlier date, then the claimant has

Window 1 Window 2 Window 3 Window 4 Window 5 Window 6 Window 7 Window 8 Window 9 Window 10Window 11

26-M

ar-0

9

1-O

ct-0

9

25-F

eb-1

0

28-J

un-1

0

8-Ja

n-07

31-M

ay-0

8

30-A

ug-0

8

4-O

ct-0

8

31-A

ug-0

7

30-S

ep-0

7

1-M

ar-0

8

12-A

pr-0

8

Original  Time for  Completion  (700  days) Extended  Duration  (568 days)

managed to mitigate part of the delay. If the completion date does not change, then the progress is on schedule and the delay is purely excusable and compensable and the culpability for any delay can then be recorded; and finally

7. This process is then repeated for other windows one by one until the last window. The analysis was performed using primavera (P3) software because this was the same software with which the baseline programme was originally prepared with ‘retained logic’ option selected during analysis as required by contract. Based on the steps stated above, the windows impact/update analysis was conducted.

6.2 Result of analysis & interpretation

A summary table showing the results of the ‘impacting’ and ‘updating’ process is provided in table 1 below. The interpretation of the results with detailed explanation is provided below on how the identification and quantification of concurrent delays, pacing delays, EOT and compensable periods are carried out. For this purpose, similar windows are grouped together for interpretation.

Table 1 – Summary of windows impact/update analysis

Group 1 – Analysis of concurrent delays (windows 1, 2, 4 & 6)

Review of the summary table above reveals that windows 1, 2, 4 and 6 are similar, in that there are concurrent delays present which means that there are excusable delays occurring concurrently with contractor culpable delays. The explanation of concurrent delay is provided with the help of a typical window (window 1), the same principle can be applied to the other windows in this group.

From To

K01A Event 2 - Car Park Delays 83 7-Dec-08 28-Feb-09 83

K01B Contractor culpable delays (slow progress delays) 87 7-Dec-08 4-Mar-09 4

K02A Event 2 - Car Park Delays 26 4-Mar-09 30-Mar-09 26

K02B Contractor pacing delays (delayed approval of lighting layouts) 42 4-Mar-09 15-Apr-09 16

K03A Event 2 - Car Park Delays 127 15-Apr-09 20-Aug-09 127

K03B No contractor culpable delays (no concurrent delays) 0 20-Aug-09 20-Aug-09 0

K04A Event 2 - Car Park Delays 16 20-Aug-09 5-Sep-09 16

K04B Contractor culpable delays (slow progress delays) 26 20-Aug-09 15-Sep-09 10

K05A No excusable delays 0 15-Sep-09 15-Sep-09 0

K05B Contractor culpable delays (slow progress delays) 32 15-Sep-09 17-Oct-09 32

K06A Event 6 - DEWA Power On delay (delayed load schedule) 38 17-Oct-09 24-Nov-09 38

K06B Contractor culpable delays (slow progress delays) 82 17-Oct-09 7-Jan-10 44

K07A No excusable delays 0 7-Jan-10 7-Jan-10 0

K07B Contractor culpable delays (slow progress delays) 32 7-Jan-10 8-Feb-10 32

K08A No excusable delays 0 8-Feb-10 8-Feb-10 0

K08B Mitigation of slow progress delays by contractor -19 8-Feb-10 20-Jan-10 -19

K09A No excusable delays 0 20-Jan-10 20-Jan-10 0

K09B Contractor culpable delays (slow progress delays) 54 20-Jan-10 15-Mar-10 54

K10A No excusable delays 0 15-Mar-10 15-Mar-10 0

K10B Contractor culpable delays (slow progress delays) 34 15-Mar-10 18-Apr-10 34

K11A No excusable delays 0 18-Apr-10 18-Apr-10 0

K11B Contractor culpable delays (slow progress delays) 71 18-Apr-10 28-Jun-10 71

290 days278 days

days

127 days

8-01-07 to 31-08-07 1

01-09-07 to 30-09-07 2

1-10-07 to 1-03-08 3

total delay from

window (Cal. days)

Delays CompletionWindow No. Programme

Name Description

4

13-04-08 to 31-05-08 5

5-10-08 to 26-03-09 8

1-06-08 to 30-08-08 6

1-09-08 to 04-10-08 7

Total Excusable Delays

2-10-09 to 25-02-10 10

26-02-10 to 28-06-10 11

27-03-09 to 01-10-09 9

Contractor Culpable DelaysTotal Delay Period

Total Compensable Delays (excusable delay with no concurrent delay)

Mitigation of delays by contractor

Only contractor culpable delay

Only contractor culpable delay

Only contractor culpable delay

(sum of impact delays)

(sum of update delays)

568(sum of impact and update delays)

Excusable compensable delays only

Concurrent delays

Only contractor culpable delay

Concurrent delays

Only contractor culpable delay

Update delay (over &

above impact delay)

Impact Delay Remarks

Concurrent delays

Concurrent delays (with alleged pacing)

2-03-08 to 12-04-08

From window 1, the 83 days of excusable delay was concurrent with 87 days of slow progress delays with slow progress delays being on the primary critical path. This means that even if we remove the effect of the excusable delays from this programme, the project would be delayed due to the contractor’s delays from this window by a period of 87 calendar days (from 07th December 2008 to 04th March 2009).

Based on the malmaison approach, the contractor was entitled to 83 calendar days of EOT from this window 1. However, based on the dominant cause approach, the contractor should not receive compensation for excusable delays during window 1 as the main cause of delay during this window was the slow progress delay by the contractor, which was driving the primary critical path. The same logic to be applied to windows 2, 4, and 6. The Claimant’s slow progress delays were driving the primary critical path within all these contemporaneous window programmes and therefore, there was EOT entitlement to the contractor of 26 days, 16 days and 38 days from window 2, 4 and 6 respectively but no compensation due to the criticality of the concurrent contractor culpable delays.

Further, the contractor had claimed that they were pacing their works during the windows 1, 2, 4 and 6 period as the car park delay event was delaying the project as a whole and they just used the available float by slowing down their progress. However, this argument by the contractor was not accepted by the expert witness appointed by the employer as the stated slow progress delays were not pacing delays due to the main reasons that the contractor could not provide any evidence to show that they informed the employer at the time of pacing of their intention to pace the works. Therefore, the pacing argument was rejected.

Scenario 3 – Excusable compensable delays only (window 3)

A review of the summary table reveals that in window 3, there was only excusable delay (delay event 3 – car park delays) affecting the window and there were no contractor culpable delays affecting the contemporaneous critical path. Therefore, based on the principles, it is considered that the Contractor is due for 127 calendar days of EOT together with compensation for this 127 calendar days.

Scenario 4 – Only contractor culpable delays (windows 5, 7, 9, 10 & 11)

In windows 5, 7, 9, 10 & 11, there were no excusable delays but only slow progress delays present. Therefore, based on the principles, it is considered that the Contractor was not entitled for EOT for delays for those windows and that the employer could claim damages in the form of LDs/penalties for the contractor culpable total delays.

Scenario 5 – Contractor’s Mitigation (window 8)

From window 8, there was no impact of the excusable delays during impacting exercise. However, when progress was updated for the window, the completion date was brought back by 19 calendar days by the mitigation of the previous slow progress delays. Therefore, this mitigation reduced the contractor’s total culpable delays by 19 calendar days.

Conclusion of the results

Based on the analysis, the contractor was entitled for an EOT of 290 calendar days due to the excusable delays and compensation for a period of 127 calendar days out of the total 290 excusable delays. LDs were applicable for the contractor culpable delays (278 calendar days). The contractor’s claim for pacing delays were rejected due to condition precedents not being met for a pacing argument to be valid which is consistent with the literature review findings.

7. Conclusions The authors have reviewed and derived conclusions from all the available important case law judgements, work of professional bodies and the interpretation by various authors on concurrency and pacing. The advantages and disadvantages of the various theories before establishing recommended guidelines for practical use have been critically evaluated. The authors suggested that each case of concurrency is unique and therefore a case to case analysis to be carried out first. The use of malmaison approach for granting EOT and dominant cause theory for quantifying compensable periods in concurrency situations was examined thoroughly. The paper proved conclusively that with the windows impact/update methodology, it was very easy to identify and quantify all aspects of delays including concurrent delays.

As a recommendation, the study was limited in that only one case study was considered due to page space constraints. Given a wider context, further research could be carried out to expand the study to a number of case studies representing a wider area of construction disputes.

References

Bramble, B. B. and Callahan, T. M. (2011) Construction Delay Claims, 4th ed., US: Wolters Kluwer.

Creswell, W. J. (2007) Qualitative Inquiry & Research Design –Choosing Among Five Approaches, 2nd ed., UK: SAGE Publications.

Denzin, N.K. and Lincoln, Y.S. (1994). “The Handbook of Qualitative Research”, p. 3.

Eyssell, K (2010) Concurrent Delay [online]. Available from http://www.charlesrussell.co.uk/UserFiles/file/pdf/Construction%20&%20Engineering/BB_sept_2010/concurrent_delay.pdf (Accessed 29 July 2013).

Farrow, T. (2001) Extension of Time Analysis – Methodology & Mythology. A paper based on a talk given to a meeting of Society of Construction Law at Manchester, UK on 6 November 2001.

Gibson, R. (2008) Construction delays – Extensions of Time and Prolongation Claims, UK: Taylor & Francis.

Keane, J. and Caletka, F. A. (2008) Delay Analysis in Construction Contracts, UK: Wiley Publications.

Kelly, M. P. (2013) Creating Mid-Period Schedules in Window Analysis using P6. The Journal of AACE International, Jan/Feb 2013.

Kheng, C.O (2003) Extension of Time and Liquidated Damages in Construction Contracts. Construction Contracts and Arbitration Seminar, The Institution of Engineers, Malaysia. 18 October 2003.

Pickavance, K. (1997) Delay and Disruption in Construction Contracts, London: LLP.

Recommended Practice (2011) 29R-03 – Forensic Schedule Analysis published by AACEI in 2011.

Rider, J.R. and Long, J.R. (2013) Analysis of concurrent/pacing delay [online]. Available from http://www.long-intl.com/articles/Long_Intl_Analysis_of_Concurrent_Pacing_Delay.pdf (accessed 15 May 2013).

SCL (2002). Society of Construction Law. Delay and Disruption Protocol. Printmost (Southern) Ltd, England (http://www.eotprotocol.com).

Thomas, R. and Wright, M. (2011) Construction Contract Claims, 3rd ed., UK: Palgrave Macmillan.

Uff, J. (2005) Construction Law, 9th ed., UK: Sweet & Maxwell.

Williamson, A. (2005) Concurrency in Construction Delays [online]. Available from http://www.keatingchambers.co.uk/resources/publications/2005/aw_concurrency_construction_delays.aspx (Accessed 13 June 2013).